Endoneurial effects of sera from patients with acute inflammatory polyradiculoneuropathy: electrophysiologic studies on normal and demyelinated rat nerves.

Serum from 10 patients with acute inflammatory demyelinative polyradiculoneuropathy (AIDP) and 10 age-matched controls was injected into rat sciatic nerve. No statistically significant changes in any electrophysiologic parameters were found at 1 week. In nerves studied with serial recordings over 60 minutes, a small but significantly greater reduction in compound muscle action potential (CMAP) was observed at 60 minutes with AIDP serum injected into normal or focally demyelinated nerves. The small reduction in CMAP amplitude in the first hour is of uncertain clinical significance.